University of Los Andes

About: University of Los Andes is a education organization based out in Bogotá, Colombia. It is known for research contribution in the topics: Population & Large Hadron Collider. The organization has 17616 authors who have published 25555 publications receiving 413463 citations.

Pedestrian traffic management of boarding and alighting in metro stations

Abstract: The objective of this work is to determine, by means of simulation and experiments, the effect of pedestrian traffic management in the boarding and alighting time of passengers at metro stations. Studies were made by means of a pedestrian traffic microsimulator (LEGION Studio) and experiments at the Human Dynamic Laboratory (HDL) of Universidad de los Andes in Santiago de Chile, to obtain criteria for the pedestrian traffic management on the platform and doors of metro cars. The methodology consists of building a boarding/alighting hall of a metro car and the relevant portion of the platform in front of the hall. The simulation scenarios included the location of the vertical handrail in the hall of the car, delimitation of a keep out zone in front of the doors and the use of differentiated doors for boarding and alighting. The results of the simulation and laboratory experiments are expressed in Pedestrian Level of Service (LOS), Passenger Service Time (PST), passenger density on the vehicle and platform, and passenger dissatisfaction. Both, the simulation results and laboratory experiments allow us to give some recommendations for the pedestrian traffic management in metro systems.

The quest rr lyrae survey. i. the first catalog

Abstract: With the 1 m Schmidt telescope of the Llano del Hato Observatory and the QUEST CCD camera, 380 deg2 of the sky have been surveyed for RR Lyrae variables in a band 23 wide in declination (centered at δ = -1°) and covering right ascensions from 41 to 61 and from 80 to 170. The bright limit (due to CCD saturation) and the faint limit are V ~ 13.5 and ~19.7, respectively, which correspond to ~4 and ~60 kpc from the Sun. We present a catalog of the positions, amplitudes, mean magnitudes, periods, and light curves of the 498 RR Lyrae variables that have been identified in this region of the sky. The majority of these stars (86%) are new discoveries. The completeness of the survey has been estimated from simulations that model the periods and light curves of real RR Lyrae variables and take into account the pattern of epochs of observation. While the completeness of the survey varies with apparent magnitude and with position, almost everywhere in the surveyed region it is quite high (>80%) for the type ab RR Lyrae variables and between 30% and 90% for the low-amplitude type c variables.

Electron and photon reconstruction and identification with the CMS experiment at the CERN LHC

Abstract: The performance is presented of the reconstruction and identification algorithms for electrons and photons with the CMS experiment at the LHC. The reported results are based on proton-proton collision data collected at a center-of-mass energy of 13 TeV and recorded in 2016-2018, corresponding to an integrated luminosity of 136 fb$^{-1}$. Results obtained from lead-lead collision data collected at $\sqrt{s_\mathrm{NN}}=$ 5.02 TeV are also presented. Innovative techniques are used to reconstruct the electron and photon signals in the detector and to optimize the energy resolution. Events with electrons and photons in the final state are used to measure the energy resolution and energy scale uncertainty in the recorded events. The measured energy resolution for electrons produced in Z boson decays in proton-proton collision data ranges from 2 to 5%, depending on electron pseudorapidity and energy loss through bremsstrahlung in the detector material. The energy scale in the same range of energies is measured with an uncertainty smaller than 0.1 (0.3)% in the barrel (endcap) region in proton-proton collisions and better than 1 (3)% in the barrel (endcap) region in heavy ion collisions. The timing resolution for electrons from Z boson decays with the full 2016-2018 proton-proton collision data set is measured to be 200 ps.